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Sun H, Zheng J, Zhang Q, Ying F, Fu Y, Guan Y, Wu J, Zhou Y, Dong J, Xu M, Yang F, An N, Shi N, Zhang L, Zhu S, Liu J, Li M. Screening of Spinal Muscular Atrophy Carriers and Prenatal Diagnosis in Pregnant Women in Yancheng, China. Biochem Genet 2024:10.1007/s10528-024-10775-9. [PMID: 38581475 DOI: 10.1007/s10528-024-10775-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/06/2024] [Indexed: 04/08/2024]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder with an autosomal recessive inheritance pattern. Patients with severe symptoms may suffer respiratory failure, leading to death. The homozygous deletion of exon 7 in the SMN1 gene accounts for nearly 95% of all cases. Population carrier screening for SMA and prenatal diagnosis by amniocentesis for high-risk couples can assist in identifying the risk of fetal disease. We provided the SMA carrier screening process to 55,447 pregnant women in Yancheng from October 2020 to December 2022. Among them, 8185 participated in this process, with a participation rate of around 14.76% (95% CI 14.47-15.06%). Quantitative real-time polymerase chain reaction (qPCR) was used to detect deletions of SMN1 exons 7 and 8 (E7, E8) in screened pregnant women. 127 were identified as carriers (111 cases of E7 and E8 heterozygous deletions, 15 cases of E7 heterozygous deletions, and 1 case of E7 heterozygous deletions and E8 homozygous deletions), resulting in a carrying rate of around 1.55% (95% CI 1.30-1.84%). After genetic counseling, 114 spouses of pregnant women who tested positive underwent SMA carrier screening; three of them were screened as SMA carriers. Multiplexed ligation-dependent probe amplification (MLPA) was used for the prenatal diagnosis of the fetuses of high-risk couples. Two of them exhibited two copies of SMN1 exon 7 (normal), and the pregnancy was continued; one exhibited no copies of SMN1 exon 7 and exon 8 (SMA patient), and the pregnancy was terminated. Analyzing SMN1 mutations in Yancheng and provide clinical evidence for SMA genetic counseling and birth defect prevention. Interventional prenatal diagnosis for high-risk families can promote informed reproductive selection and prepare for the fetus's early treatment.
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Affiliation(s)
- Huilin Sun
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jianli Zheng
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Qing'e Zhang
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Feifei Ying
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Yadong Fu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Yongjuan Guan
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jing Wu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Yueyun Zhou
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jingjing Dong
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Mengjun Xu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Fangfang Yang
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Ning An
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Ning Shi
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Lu Zhang
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Shu Zhu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China
| | - Jianbing Liu
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China.
| | - Min Li
- The Affiliated Yancheng Maternity&Child Health Hospital of Yangzhou University Medical School, Yancheng, 224001, China.
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Yalcintepe S, Karal Y, Demir S, Atli EI, Atli E, Eker D, Mail C, Zhuri D, Guler HS, Gurkan H. The Frequency of SMN1, SMN2 Copy Numbers in 246 Turkish Cases Analyzed with MLPA Method. Glob Med Genet 2023; 10:117-122. [PMID: 37332684 PMCID: PMC10275673 DOI: 10.1055/s-0043-1770055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2023] Open
Abstract
This study aimed to define the copy numbers of SMN1 and SMN2 genes and the diagnosis rate and carrier frequency of spinal muscular atrophy (SMA) in the Thrace region of Turkey. In this study, the frequency of deletions in exons 7 and 8 in the SMN1 gene and SMN2 copy numbers were investigated. A total of 133 cases with the preliminary diagnosis of SMA and 113 cases with the suspicion of being an SMA carrier from independent families were analyzed by multiplex ligation-dependent probe amplification method for SMN1 and SMN2 gene copy numbers. SMN1 homozygous deletions were detected in 34 patients (25.5%) of 133 cases with the suspicion of SMA. Cases diagnosed with SMA type I was 41.17% (14/34), 29.4% (10/34) with type II, 26.4% (9/34) with type III, and 2.94% (1/34) with type IV. The SMA carrier rate was 46.01% in 113 cases. In 34 SMA cases, SMN2 copy numbers were: two copies - 28 cases (82.3%), three copies - 6 cases (17.6%). SMN2 homozygous deletions were detected in 15% (17/113) of carrier analysis cases. The consanguinity rate of the parents was 23.5% in SMA diagnosed cases. In this study, we had a 25.5% of SMA diagnosis rate and 46% SMA carrier frequency. The current study also showed the relatively low consanguinity rate of the Thrace region, with 23.5% according to the east of Turkey.
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Affiliation(s)
- Sinem Yalcintepe
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Yasemin Karal
- Department of Pediatric Neurology, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Selma Demir
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Emine Ikbal Atli
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Engin Atli
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Damla Eker
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Cisem Mail
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Drenushe Zhuri
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Hazal Sezginer Guler
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Hakan Gurkan
- Department of Medical Genetics, Faculty of Medicine, Trakya University, Edirne, Turkey
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Bai Y, Sun Y, Liu N, Wang L, Jiao Z, Hou Y, Duan H, Li Q, Zhu X, Meng J, Kong X. Genetic analysis of 55 cases with fetal skeletal dysplasia. Orphanet J Rare Dis 2022; 17:410. [PMID: 36352425 PMCID: PMC9648031 DOI: 10.1186/s13023-022-02559-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 10/23/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Fetal skeletal dysplasia (SD) is a common congenital disability comprising a complex group of skeletal disorders with substantial clinical and genetic heterogeneity. Many of these defects are detected prenatally using ultrasound (US). However, the diagnostic accuracy of the US is limited. METHODS We recruited 55 unrelated fetuses with US-detected skeletal anomalies and performed sequential tests using copy number variation sequencing, targeted skeletal gene panel sequencing, or whole exome sequencing. The detected variants were validated using Sanger sequencing or multiplex ligation-dependent probe amplification. We conducted breakpoint analysis and structural modeling of variants possibly involved in fetal SD. RESULTS A definitive diagnosis was achieved in 81.82% of affected fetuses (45/55). We identified chromosomal abnormalities in seven cases and 36 variants, of which 18 were novel pathogenic or likely pathogenic in 11 genes in 38 cases. De novo variants were identified in 27 cases (71.05%, 27/38), and one gonosomal mosaicism variant was found in the mother of one fetus. Our case examples demonstrated the high heterogeneity of fetal SDs and the rare fetal SD-associated challenges. CONCLUSIONS Careful clinical evaluation of fetuses with SD can guide appropriate molecular testing. Our study extends the SD-associated pathogenic variant spectrum and provides useful genetic counselling guidance and an accurate prenatal diagnosis strategy.
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Affiliation(s)
- Ying Bai
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Yue Sun
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Ning Liu
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Li Wang
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Zhihui Jiao
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Yaqin Hou
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Huikun Duan
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Qianqian Li
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Xiaofan Zhu
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Jingjing Meng
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
| | - Xiangdong Kong
- grid.412633.10000 0004 1799 0733Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 China
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Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in SMN1 (encoding survival motor neuron protein (SMN)). Reduced expression of SMN leads to loss of α-motor neurons, severe muscle weakness and often early death. Standard-of-care recommendations for multidisciplinary supportive care of SMA were established in the past few decades. However, improved understanding of the pathogenetic mechanisms of SMA has led to the development of different therapeutic approaches. Three treatments that increase SMN expression by distinct molecular mechanisms, administration routes and tissue biodistributions have received regulatory approval with others in clinical development. The advent of the new therapies is redefining standards of care as in many countries most patients are treated with one of the new therapies, leading to the identification of emerging new phenotypes of SMA and a renewed characterization of demographics owing to improved patient survival.
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Li S, Han X, Xu Y, Chang C, Gao L, Li J, Lu Y, Mao A, Wang Y. Comprehensive Analysis of Spinal Muscular Atrophy: SMN1 Copy Number, Intragenic Mutation, and 2 + 0 Carrier Analysis by Third-Generation Sequencing. J Mol Diagn 2022; 24:1009-1020. [PMID: 35659528 DOI: 10.1016/j.jmoldx.2022.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/14/2022] [Accepted: 05/16/2022] [Indexed: 01/18/2023] Open
Abstract
Population-wide carrier screening for spinal muscular atrophy (SMA) is recommended by the American College of Medical Genetics and Genomics. However, the methods used currently mainly focus on SMN1 copy number and fail to identify carriers with pathogenic intragenic mutations and silent (2 + 0) carriers. We developed a method termed comprehensive analysis of SMA (CASMA) based on long-range PCR and third-generation sequencing of full-length and downstream regions of SMN1/2. The sensitivity and specificity of CASMA to detect SMA carriers with one copy of SMN1 were 100% (n = 101) and 99.2% (n = 236), respectively. CASMA confirmed three SMN1 intragenic mutations and pinpointed an inframe mutation c.661_666del to SMN2, which was misreported to SMN1 by allele-specific long-range nested PCR plus Sanger sequencing. CASMA also correctly predicted 8 of 16 samples (50%) with SMN1 duplication alleles. CASMA was expected to increase the detection rate of SMA carriers from 91% to 98% and decrease the residual risk ratio from 1:415 to 1:1868 after negative results of two SMN1 copies in the Chinese population. CASMA presents a comprehensive approach for identifying SMN1 and SMN2 copy number, intragenic mutations, and potential silent carriers that significantly reduces the residual risk ratio in SMA carrier screening and has great clinical utility.
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Affiliation(s)
- Shuyuan Li
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China; Institute of Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xu Han
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China; Institute of Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Xu
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China; Institute of Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chunxin Chang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China; Institute of Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Li Gao
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China; Institute of Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jiaqi Li
- Berry Genomics Corporation, Beijing, China
| | - Yulin Lu
- Berry Genomics Corporation, Beijing, China
| | - Aiping Mao
- Berry Genomics Corporation, Beijing, China.
| | - Yanlin Wang
- International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China; Institute of Birth Defects and Rare Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
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Bai Y, Liu J, Xu J, Sun Y, Li J, Gao Y, Liu L, Jia C, Kong X, Wang L. Long-Read Sequencing Revealed Extragenic and Intragenic Duplications of Exons 56-61 in DMD in an Asymptomatic Male and a DMD Patient. Front Genet 2022; 13:878806. [PMID: 35615378 PMCID: PMC9125615 DOI: 10.3389/fgene.2022.878806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Expanded carrier screening (ECS) has become an increasingly common technique to assess the genetic risks of individuals in the prenatal or preconception period. Unexpected variants unrelated to referral are being increasingly detected in asymptomatic individuals through ECS. In this study, we reported an asymptomatic male with duplication of exons 56-61 in the DMD gene through ECS using whole-exome sequencing (WES), which was also detected in a male patient diagnosed with typical Duchenne muscular dystrophy (DMD). Breakpoint analysis was then performed to explore the potential mechanisms of phenotypic differences using long-read sequencing (LRS), PacBio single-molecule real-time (PacBio SMRT) target sequencing, and Sanger sequencing. Complex structural variations (SVs) on chromosome X were identified in the asymptomatic male, which revealed that the duplication occurred outside the DMD gene; whereas, the duplication in the patient with DMD was a tandem repeat. The phenotypic differences between the two men could be explained by the different breakpoint junctions. To the best of our knowledge, this is the first report of a breakpoint analysis of DMD duplication in two men with different phenotypes. Breakpoint analysis is necessary when the clinical phenotypes are inconsistent with genotypes, and it applies to prenatal testing.
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Affiliation(s)
- Ying Bai
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ju Liu
- Department of Neurology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jinghan Xu
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yue Sun
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jingjing Li
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yong Gao
- GrandOmics Biosciences, Beijing, China
| | - Lina Liu
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | | | - Xiangdong Kong
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Li Wang
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Hu L, Mao S, Lin L, Bai G, Liu B, Mao J. Stress granules in the spinal muscular atrophy and amyotrophic lateral sclerosis: The correlation and promising therapy. Neurobiol Dis 2022; 170:105749. [PMID: 35568100 DOI: 10.1016/j.nbd.2022.105749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 03/27/2022] [Accepted: 05/05/2022] [Indexed: 10/18/2022] Open
Abstract
Increasing genetic and biochemical evidence has broadened our view of the pathomechanisms that lead to Spinal muscular atrophy (SMA) and Amyotrophic lateral sclerosis (ALS), two fatal neurodegenerative diseases with similar symptoms and causes. Stress granules are dynamic cytosolic storage hubs for mRNAs in response to stress exposures, that are evolutionarily conserved cytoplasmic RNA granules in somatic cells. A lot of previous studies have shown that the impaired stress granules are crucial events in SMA/ALS pathogenesis. In this review, we described the key stress granules related RNA binding proteins (SMN, TDP-43, and FUS) involved in SMA/ALS, summarized the reported mutations in these RNA binding proteins involved in SMA/ALS pathogenesis, and discussed the mechanisms through which stress granules dynamics participate in the diseases. Meanwhile, we described the applications and limitation of current therapies targeting SMA/ALS. We futher proposed the promising targets on stress granules in the future therapeutic interventions of SMA/ALS.
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Affiliation(s)
- LiDan Hu
- the Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China.
| | - Shanshan Mao
- the Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Li Lin
- the Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Guannan Bai
- the Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Bingjie Liu
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianhua Mao
- the Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China
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8
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The Importance of Digging into the Genetics of SMN Genes in the Therapeutic Scenario of Spinal Muscular Atrophy. Int J Mol Sci 2021; 22:ijms22169029. [PMID: 34445733 PMCID: PMC8396600 DOI: 10.3390/ijms22169029] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
After 26 years of discovery of the determinant survival motor neuron 1 and the modifier survival motor neuron 2 genes (SMN1 and SMN2, respectively), three SMN-dependent specific therapies are already approved by FDA and EMA and, as a consequence, worldwide SMA patients are currently under clinical investigation and treatment. Bi-allelic pathogenic variants (mostly deletions) in SMN1 should be detected in SMA patients to confirm the disease. Determination of SMN2 copy number has been historically employed to correlate with the phenotype, predict disease evolution, stratify patients for clinical trials and to define those eligible for treatment. In view that discordant genotype-phenotype correlations are present in SMA, besides technical issues with detection of SMN2 copy number, we have hypothesized that copy number determination is only the tip of the iceberg and that more deepen studies of variants, sequencing and structures of the SMN2 genes are necessary for a better understanding of the disease as well as to investigate possible influences in treatment responses. Here, we highlight the importance of a comprehensive approach of SMN1 and SMN2 genetics with the perspective to apply for better prediction of SMA in positive neonatal screening cases and early diagnosis to start treatments.
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Kimizu T, Ida S, Okamoto K, Awano H, Niba ETE, Wijaya YOS, Okazaki S, Shimomura H, Lee T, Tominaga K, Nabatame S, Saito T, Hamazaki T, Sakai N, Saito K, Shintaku H, Nozu K, Takeshima Y, Iijima K, Nishio H, Shinohara M. Spinal Muscular Atrophy: Diagnosis, Incidence, and Newborn Screening in Japan. Int J Neonatal Screen 2021; 7:ijns7030045. [PMID: 34287247 PMCID: PMC8293226 DOI: 10.3390/ijns7030045] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 11/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder that causes degeneration of anterior horn cells in the human spinal cord and subsequent loss of motor neurons. The severe form of SMA is among the genetic diseases with the highest infant mortality. Although SMA has been considered incurable, newly developed drugs-nusinersen and onasemnogene abeparvovec-improve the life prognoses and motor functions of affected infants. To maximize the efficacy of these drugs, treatments should be started at the pre-symptomatic stage of SMA. Thus, newborn screening for SMA is now strongly recommended. Herein, we provide some data based on our experience of SMA diagnosis by genetic testing in Japan. A total of 515 patients suspected of having SMA or another lower motor neuron disease were tested. Among these patients, 228 were diagnosed as having SMA with survival motor neuron 1 (SMN1) deletion. We analyzed the distribution of clinical subtypes and ages at genetic testing in the SMN1-deleted patients, and estimated the SMA incidence based on data from Osaka and Hyogo prefectures, Japan. Our data showed that confirmed diagnosis by genetic testing was notably delayed, and the estimated incidence was 1 in 30,000-40,000 live births, which seemed notably lower than in other countries. These findings suggest that many diagnosis-delayed or undiagnosed cases may be present in Japan. To prevent this, newborn screening programs for SMA (SMA-NBS) need to be implemented in all Japanese prefectures. In this article, we also introduce our pilot study for SMA-NBS in Osaka Prefecture.
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Affiliation(s)
- Tomokazu Kimizu
- Department of Pediatric Neurology, Osaka Women’s and Children’s Hospital, 840 Murodocho, Izumi 594-1101, Japan;
| | - Shinobu Ida
- Department of Gastroenterology and Endocrinology, Osaka Women’s and Children’s Hospital, 840 Murodocho, Izumi 594-1101, Japan;
| | - Kentaro Okamoto
- Department of Pediatrics, Ehime Prefectural Imabari Hospital, 4-5-5 Ishiicho, Imabari 794-0006, Japan;
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan; (H.A.); (K.N.); (K.I.)
| | - Emma Tabe Eko Niba
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan; (E.T.E.N.); (Y.O.S.W.); (M.S.)
| | - Yogik Onky Silvana Wijaya
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan; (E.T.E.N.); (Y.O.S.W.); (M.S.)
| | - Shin Okazaki
- Department of Pediatric Neurology, Children’s Medical Center, Osaka City General Hospital, 2-13-22 Miyakojimahondori, Osaka 534-0021, Japan;
| | - Hideki Shimomura
- Department of Pediatrics, Hyogo College of Medicine, 1-1 Mukogawacho, Nishinomiya 663-8501, Japan; (H.S.); (T.L.); (Y.T.)
| | - Tomoko Lee
- Department of Pediatrics, Hyogo College of Medicine, 1-1 Mukogawacho, Nishinomiya 663-8501, Japan; (H.S.); (T.L.); (Y.T.)
| | - Koji Tominaga
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita 565-0871, Japan; (K.T.); (S.N.)
| | - Shin Nabatame
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita 565-0871, Japan; (K.T.); (S.N.)
| | - Toshio Saito
- Division of Child Neurology, Department of Neurology, National Hospital Organization Osaka Toneyama Medical Center, 5-1-1 Toneyama, Toyonaka 560-8552, Japan;
| | - Takashi Hamazaki
- Department of Pediatrics, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Osaka 545-8585, Japan; (T.H.); (H.S.)
| | - Norio Sakai
- Child Healthcare and Genetic Science Laboratory, Division of Health Sciences, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita 565-0871, Japan;
| | - Kayoko Saito
- Institute of Medical Genetics, Tokyo Women’s Medical University, 8-1 Kawadacho, Tokyo 162-0054, Japan;
| | - Haruo Shintaku
- Department of Pediatrics, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Osaka 545-8585, Japan; (T.H.); (H.S.)
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan; (H.A.); (K.N.); (K.I.)
| | - Yasuhiro Takeshima
- Department of Pediatrics, Hyogo College of Medicine, 1-1 Mukogawacho, Nishinomiya 663-8501, Japan; (H.S.); (T.L.); (Y.T.)
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan; (H.A.); (K.N.); (K.I.)
- Hyogo Prefectural Kobe Children’s Hospital, 1-6-7 Minatojima Minamimachi, Kobe 650-0047, Japan
| | - Hisahide Nishio
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan; (E.T.E.N.); (Y.O.S.W.); (M.S.)
- Faculty of Medical Rehabilitation, Kobe Gakuin University, 518 Arise Ikawadani-cho, Kobe 651-2180, Japan
- Correspondence: ; Tel.: +81-789-745-073
| | - Masakazu Shinohara
- Department of Community Medicine and Social Healthcare Science, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan; (E.T.E.N.); (Y.O.S.W.); (M.S.)
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